Sustained release water marking device for search and rescue

Abstract

A device that can provide sustained release of a detectable marker into a surrounding body of water as well as methods of forming the device and methods of using the device. The devices and methods can be utilized to locate people or vessels, e.g., by search and rescue personnel, following the disabling of air or water vessels of any type or size on/in a body of water. The devices include multiple, separated layers that each include a detectable marker, e.g., a fluorescent dye. The dye-containing layers are separated from one another and sequentially released over a predetermined controlled period of time and as such the device can continue to release a detectable marker over an extended period of time into surrounding water.

What is claimed is: 
     
       1. A device for providing sustained release of a detectable marker in a body of water comprising:
 a container; 
 a first layer within the container, the first layer comprising a first detectable marker; 
 a second layer within the container, the second layer comprising a second detectable marker admixed with a first buoyant, dissolvable matrix; and 
 an intermediate layer separating the first and second layers, the intermediate layer comprising a first sub-layer and a second sub-layer, the first sub-layer comprising a water-absorbent material, the second sub-layer comprising an effervescent material that forms a gas upon contact with water. 
 
     
     
       2. The device of  claim 1 , wherein at least one of the first detectable marker and the second detectable marker comprise a fluorescent dye. 
     
     
       3. The device of  claim 1 , the water-absorbent material comprising a cellulose or a ligno-cellulose material. 
     
     
       4. The device of  claim 1 , the intermediate layer comprising a water-soluble polymer. 
     
     
       5. The device of  claim 1 , further comprising an attachment configured to attach the container to a surface. 
     
     
       6. The device of  claim 5 , wherein the attachment is capable of pivoting in one or more degrees of freedom. 
     
     
       7. The device of  claim 1 , further comprising a cover configured to protect an open end of the container. 
     
     
       8. The device of  claim 1 , the buoyant, dissolvable matrix comprising a surfactant. 
     
     
       9. The device of  claim 1 , further comprising a third layer that comprises a third detectable marker that can be the same or different as the first detectable marker and/or the second detectable marker and an additional intermediate layer separating the second and third layers. 
     
     
       10. The device of  claim 9 , wherein the third layer includes the third detectable marker admixed with a second buoyant, dissolvable matrix. 
     
     
       11. The device of  claim 10 , wherein the admixture of the second detectable marker and the first buoyant, dissolvable matrix are in the form of first particles, and/or the admixture of the third detectable marker and the second buoyant, dissolvable matrix are in the form of second particles. 
     
     
       12. The device of  claim 9 , further comprising one or more additional layers. 
     
     
       13. A method for releasing a detectable marker into a body of water over a sustained period of time, the method including locating the device of  claim 1  on a vessel, wherein upon sustained or intermittent contact of the interior of the container with water, the first detectable marker of the first layer is discharged from the container, following which the water contacts the intermediate layer for a first period of time, following which the intermediate layer is dissolved and/or discharged from the container, and following which, the water contacts the second layer, upon which the second detectable marker is discharged from the container into the surrounding water whereupon the first buoyant, dissolvable matrix dissolves over a second period of time and releases the second detectable marker. 
     
     
       14. The device of  claim 1 , wherein the first detectable marker and the second detectable marker are the same material. 
     
     
       15. The device of  claim 1 , wherein the first detectable marker and the second detectable marker are different materials. 
     
     
       16. The device of  claim 1 , the first sub-layer comprising a material that dissolves upon contact with water. 
     
     
       17. The device of  claim 1 , the effervescent material comprising a carbonate salt, a bicarbonate salt, a citric acid, an alkali metal acid citrate, a tartaric acid, an alkali metal bisulfate, or a combination thereof. 
     
     
       18. A method for forming a water marking device comprising:
 forming a first layer in a container, the first layer comprising a first detectable marker admixed with a first buoyant, dissolvable matrix; 
 forming a first sub-layer adjacent to the first layer, the first sub-layer comprising an effervescent material that forms a gas upon contact with water; 
 forming a second sub-layer adjacent to the first sub-layer such that the first sub-layer is between the first layer and the second sub-layer, the second sub-layer comprising a water-absorbent material; and 
 forming a second layer adjacent to the second sub-layer such that the first and second sub-layers are between the first and second layers, the second layer comprising a second detectable marker. 
 
     
     
       19. The method of  claim 18 , the second layer comprising the second detectable marker admixed with a second buoyant, dissolvable matrix. 
     
     
       20. The method of  claim 19 , wherein the first buoyant, dissolvable matrix dissolves in water more slowly than the second buoyant, dissolvable matrix. 
     
     
       21. The method of  claim 18 , further comprising attaching the container to a vessel, a floatation device or outerwear.